Substance Use Disorders (SUDs) are common in Veterans Health Administration (VHA) patients and are closely linked to some of the most pressing problems facing Veterans including overdose, suicide risk and homelessness. The VHA is a national leader in providing access to high-quality SUD treatment as well as the development of an evidence-base to inform and improve care for Veterans with SUDs. However, key gaps remain, particularly for Veterans who have co-occurring SUDs and psychiatric and/or medical conditions. Nonetheless, there is the clear potential to expand the positive impact of substance- oriented services within the VA by improving access to behavioral health treatments and integrating these services into addictions treatment. Mark Ilgen, Ph.D. has developed a research portfolio focused on tailoring SUD treatment to address patient comorbidity by conducting Veteran-centric health services research on addiction. The two primary thematic aims of this work are: Aim 1: to improve treatment outcomes and reduce risk of adverse events among Veterans with co-occurring SUDs and chronic pain; and, Aim 2: to decrease the risk of suicide among Veterans with SUDs. These two thematic areas directly relate to positive treatment outcomes, as well as reducing the likelihood of adverse events, among Veterans with SUDs. Dr. Ilgen's contributions to these areas are evidenced by his grant-funded research with support from the VA Health Services Research and Development (HSR&D), the Department of Defense and the National Institute on Drug Abuse, in addition to over 165 peer-reviewed scientific publications. Dr. Ilgen has actively mentored nine early career investigators and/or trainees within the VA and has held key administrative positions within the Ann Arbor VA Center of Innovation (COIN), as a member of the leadership team and the co-lead of the Mentorship Core. Given his active and productive research portfolio, as well as his demonstrated commitment to mentoring colleagues in developing VA research careers, Dr. Ilgen is a strong candidate for a Health Services Research Career Scientist Award. The proposed Research Career Scientist Award will support his continued research, as well an expanded role in mentorship and training of the next generation of HSR&D researchers. This research portfolio has the potential to address some of the most-critical and vexing behavioral health-related priorities in VHA and improve care for some of the most challenging and highest-risk Veterans treated within the VHA system.